Washing machine

ABSTRACT

A washing machine in which a coupling structure between a subsidiary washing tub and a rotary tub is improved. The washing machine includes a cabinet configured to form an exterior, a tub included in the cabinet and configured to contain washing water, a rotary tub included in the tub and configured to receive laundry, a driving device configured to rotate the rotary tub, a subsidiary washing tub included in the rotary tub and coupled to be removable from the rotary tub, and a connection shaft configured to extend from a lower portion of the rotary tub to couple the subsidiary washing tub to the rotary tub, such that the subsidiary washing tub is rotated together with the rotary tub.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No. 10-2014-0009838, filed on Jan. 27, 2014, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

1. Field

Embodiments of the present invention relate to a washing machine, and more particularly, to a washing machine which includes a subsidiary washing tub included in a rotary tub.

2. Description of the Related Art

Washing machines are apparatuses which wash laundry using electric power. In general, the washing machines may be classified into full automation type washing machines in which laundry and washing water are stirred through the rotation of a pulsator to generate a washing water current and wash the laundry, and drum type washing machines in which the laundry falls through a lifter formed at a drum and thus, the laundry is washed.

The full automation type washing machine includes a tub configured to contain washing water, a rotary tub rotatably installed in the tub, a pulsator rotatably installed at a bottom of the rotary tub, and a driving device configured to rotatably drive the rotary tub and the pulsator.

When the laundry and the washing water are put into the rotary tub, then the rotary tub and the pulsator are rotated, the laundry and the washing water put into the rotary tub are stirred together, and dirt on the laundry is removed.

Recently, the laundry may be sorted and separately washed by installing a subsidiary washing tub in the rotary tub. Since the laundry may be separately washed according to types thereof, this has an advantage in which it is efficient in temporal and economic aspects, when a user uses the washing machine.

However, in the washing of the laundry in a conventional subsidiary washing tub, the laundry in the subsidiary washing tub may be washed by rotation of the rotary tub. In this case, since the laundry in the subsidiary washing tub is washed by only the rotation of the rotary tub, washing performance of the laundry in the subsidiary washing tub is lowered.

The pulsator of the subsidiary washing tub may be separately installed at an upper end of the washing machine. However, in this case, when spin-drying the laundry, the pulsator of the subsidiary washing tub should be moved upward and separated from the subsidiary washing tub in order to prevent twisting of the laundry.

Further, a removable washing net may be foldably installed at the washing tub. However, in this case, the laundry may be washed while being separated spatially, but contaminated washing water is not separated in the washing process.

SUMMARY

Additional aspects and/or advantages will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the invention.

Therefore, it is an aspect of the present invention to provide a washing machine in which a coupling structure between a subsidiary washing tub and a rotary tub may be improved to enhance the washing power of laundry in the subsidiary washing tub.

Additional aspects of the invention will be set forth in part by the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

In accordance with one aspect of the present invention, a washing machine includes a cabinet configured to form an exterior, a tub included in the cabinet to contain washing water, a rotary tub included in the tub to receive laundry, a driving device configured to rotate the rotary tub, a subsidiary washing tub included in the rotary tub and coupled to be removable from the rotary tub, and a connection shaft configured to extend from a lower portion of the rotary tub to couple the subsidiary washing tub to the rotary tub, such that the subsidiary washing tub is rotated together with the rotary tub.

The rotary tub may further include a first pulsator rotatably installed at the lower portion of the rotary tub to generate a water current and circulate the laundry.

The connection shaft may extend from a center portion of the first pulsator.

The subsidiary washing tub may further include a second pulsator rotatably included at a lower portion of the subsidiary washing tub to generate a water current and circulate the laundry.

The connection shaft may be coupled to a lower portion of the second pulsator.

The connection shaft may include a base portion coupled to the first pulsator, a neck portion configured to extend from the base portion, and a head portion configured to extend from the neck portion and coupled to the subsidiary washing tub.

The head portion may be provided so that a width of the head portion tapers toward an end thereof to guide coupling to the subsidiary washing tub.

A coupling hole to which the connection shaft is coupled may be formed at a lower surface of the subsidiary washing tub.

A sealing member configured to seal the coupling hole may be coupled inside the subsidiary washing tub.

A coupling groove to which the connection shaft is coupled may be formed at a lower surface of the subsidiary washing tub.

The washing machine may further include a balancer included on the tub, and the subsidiary washing tub may be removably coupled to the balancer.

At least one protruding portion may be provided along a circumference of the subsidiary washing tub, and the balancer may have at least one receiving groove to accommodate the protruding portion.

A magnet may be included inside the receiving groove, and a magnetic member reacting with the magnet may be included inside the protruding portion, and the subsidiary washing tub and the balancer may be coupled to each other by a magnetic force.

In accordance with another aspect of the present invention, a washing machine includes a cabinet configured to form an exterior, a tub included in the cabinet and configured to contain washing water, a rotary tub included in the tub, configured to receive laundry, and including a first pulsator configured to generate a water current and circulate laundry, a driving device configured to rotate the rotary tub, a subsidiary washing tub included in the rotary tub and coupled to be removable from the rotary tub and including a second pulsator configured to generate a water current and circulate laundry, and a connection shaft configured to extend from the first pulsator and connect the first pulsator and the second pulsator so that the first pulsator and the second pulsator are interlocked and rotated together.

The connection shaft may include a base portion coupled to the first pulsator, a neck portion configured to extend from the base portion, and a head portion configured to extend from the neck portion and coupled to the subsidiary washing tub.

A coupling hole through which the head portion of the connection shaft passes may be formed at a lower surface of the subsidiary washing tub, and the washing machine may further include a sealing member configured to seal the coupling hole.

A coupling groove to which the connection shaft is coupled may be formed at a lower surface of the subsidiary washing tub.

The washing machine may further include a balancer included on the tub, wherein the subsidiary washing tub is removably coupled to the balancer.

At least one protruding portion may be provided along a circumference of the subsidiary washing tub, and the balancer may have at least one receiving groove to accommodate the protruding portion, and the subsidiary washing tub and the balancer may be coupled to each other by coupling the protruding portion and the receiving groove.

A magnet may be included inside the receiving groove, and a magnetic member reacting with the magnet may be included inside the protruding portion, and the subsidiary washing tub and the balancer may be coupled to each other by a magnetic force.

In accordance with another aspect of the present invention, a washing machine comprising includes a cabinet configured to form an exterior; a tub included in the cabinet and configured to contain washing water; a rotary tub included in the tub and configured to receive first laundry, the rotary tub including a first pulsator rotatably installed at the lower portion of the rotary tub to generate a first water current and circulate the first laundry; a driving device configured to rotate the rotary tub; a subsidiary washing tub included in the rotary tub and coupled to be removable from the rotary tub, the subsidiary washing tub including a second pulsator rotatably included at a lower portion of the subsidiary washing tub to generate a second water current and circulate second laundry; and a connection shaft configured to extend from a center portion of the first pulsator to a lower portion of the second pulsator to couple the subsidiary washing tub to the rotary tub, such that the subsidiary washing tub is rotated together with the rotary tub.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects of the invention will become apparent and more readily appreciated from the following descriptions of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a cross-sectional view of a washing machine in accordance with an embodiment of the present invention;

FIG. 2 is a view illustrating a coupling state of a rotary tub and a subsidiary washing tub in the washing machine in accordance with the embodiment of the present invention;

FIG. 3 is an exploded view illustrating a disassembled state of the rotary tub and the subsidiary washing tub in the washing machine in accordance with the embodiment of the present invention;

FIG. 4 is a cross-sectional view illustrating a coupling state of a first pulsator and the subsidiary washing tub in the washing machine in accordance with the embodiment of the present invention;

FIG. 5 is a view illustrating a disassembled state of a balancer and the subsidiary washing tub in the washing machine in accordance with the embodiment of the present invention;

FIG. 6 is a view illustrating a coupling state of a rotary tub and a subsidiary washing tub in a washing machine in accordance with another embodiment of the present invention;

FIG. 7 is an exploded view illustrating a disassembled state of the rotary tub and the subsidiary washing tub in the washing machine in accordance with another embodiment of the present invention; and

FIG. 8 is a cross-sectional view illustrating a coupling state of a first pulsator and the subsidiary washing tub in the washing machine in accordance with another embodiment of the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

FIG. 1 is a cross-sectional view of a washing machine in accordance with an embodiment of the present invention.

As illustrated in FIG. 1, a washing machine 1 includes a cabinet 10 configured to form an exterior, a tub 20 included in the cabinet 10 and configured to contain washing water, a rotary tub 30 rotatably included in the tub 20, and a driving device 40 configured to drive the rotary tub 30.

In an embodiment, an upper cover 15 having a laundry input opening 14 through which laundry is put into the rotary tub 30 is provided on the cabinet 10, and a door 16 configured to open and close the laundry input opening 14 is provided at the upper cover 15.

A lower cover 18 coupled to a mounting portion 19 configured to mount the washing machine 1 on a floor surface is provided under the cabinet 10.

A suspension member (not shown) configured to suspend and support the rotary tub 30 in the cabinet 10 is connected to an upper portion of the cabinet 10.

The rotary tub 30 is rotatably included in the cabinet 10, and a plurality of through-holes (not shown) formed along a circumference of the rotary tub 30 are formed at an upper portion thereof.

A balancer 90 may be provided on the rotary tub 30.

A subsidiary washing tub 80 which is removable from the rotary tub 30 may be coupled to the balancer 90. When the subsidiary washing tub 80 is coupled to the balancer 90, the subsidiary washing tub 80 is located in the rotary tub 30. Therefore, different types of laundry may be separately received and washed in the rotary tub 30 and the subsidiary washing tub 80, respectively. The subsidiary washing tub 80 may be separated from the balancer 90 and then used as a laundry storage basket for storing the laundry before and after a washing process.

A connection shaft 70 which couples the rotary tub 30 and the subsidiary washing tub 80 so that the subsidiary washing tub 80 is rotated together with the rotary tub 30 may be included between the rotary tub 30 and the subsidiary washing tub 80. This will be described later.

A first pulsator 71 is rotatably installed at a bottom of the rotary tub 30. The first pulsator 71 serves to stir the laundry put into the rotary tub 30 together with the washing water.

A water feed device 50 configured to supply the washing water into the rotary tub 30 is installed above the rotary tub 30. The water feed device 50 includes a water feed valve 53 configured to control water supply, and a water pipe 51 configured to connect the water feed valve 53 to a detergent supply device 60.

One side of the water pipe 51 is connected to an external water source (not shown), and the other side thereof is connected to the detergent supply device 60. The detergent supply device 60 includes a case 63 included in the upper cover 15, and a detergent container 61 which is removably installed in the case 63 to contain each detergent. An outlet port 65 configured to discharge the washing water in which the detergent is dissolved is formed at a lower surface of the case 63.

Water fed through the water pipe 51 is fed into the rotary tub 30 together with the detergent via the detergent supply device 60.

A first discharge hose 82 and a second discharge hose 84 configured to guide the washing water to an outside of the cabinet 10 after completion of a washing or drying process are provided under the rotary tub 30.

The driving device 40 includes a clutch 120 configured to selectively rotate the rotary tub 30 and the first pulsator 71, a driving motor 150 configured to drive the clutch 120, a flange member 140 configured to connect a driving shaft 124 of the clutch 120 to a bottom portion of the rotary tub 30 so as to transmit a rotational force of the driving shaft 124 to the rotary tub 30, and a base plate 160 configured to fix the clutch 120 and the driving motor 150.

FIG. 2 is a view illustrating a coupling state of the rotary tub and the subsidiary washing tub in the washing machine in accordance with the embodiment of the present invention.

FIG. 3 is an exploded view illustrating a disassembled state of the rotary tub and the subsidiary washing tub in the washing machine in accordance with the embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a coupling state of the first pulsator and the subsidiary washing tub in the washing machine in accordance with the embodiment of the present invention.

As illustrated in FIGS. 2 to 4, in an embodiment, the first pulsator 71 is coupled to the bottom of the rotary tub 30. Further, the balancer 90 may be coupled to an upper surface of the rotary tub 30. The subsidiary washing tub 80 is coupled to the balancer 90, and thus the subsidiary washing tub 80 is located in the rotary tub 30.

The balancer 90 may be formed by coupling a body portion 93 a to a cover portion 93 b. The balancer 90 and the subsidiary washing tub 80 may be coupled to each other through a protruding portion 81 of the subsidiary washing tub 80 and a receiving groove 91 of the balancer 90. This will be described later.

A frame portion 88 may be provided at an upper surface of the subsidiary washing tub 80. The frame portion 88 may be located at an upper surface of the balancer 90. The frame portion 88 may be provided to protrude from a surface of the subsidiary washing tub 80.

A plurality of through-holes 80 a may be provided at an upper portion of a cylindrical portion of the subsidiary washing tub 80. Further, the cylindrical portion of the subsidiary washing tub 80 may be formed to be sloped. Therefore, when the subsidiary washing tub 80 is rotated, the washing water in the subsidiary washing tub 80 may be discharged by centrifugal force through the through-holes 80 a. That is, when the washing water is fed into the subsidiary washing tub 80 and a water level of the washing water in the subsidiary washing tub 80 is more than a predetermined value, the washing water is fed into the rotary tub 30 through the through-holes 80 a of the subsidiary washing tub 80.

The first pulsator 71 of the rotary tub 30 may be formed in a disc shape and included on a lower surface of the rotary tub 30. A plurality of through-holes 71 a may be formed in an entire portion of the first pulsator 71 so that the washing water passes and flows up and down through the first pulsator 71.

Further, the connection shaft 70 may be provided to extend from a center portion of the first pulsator 71. The driving shaft 124 may be coupled to the center portion of the first pulsator 71. The driving shaft 124 may be coupled to a lower portion of the connection shaft 70. Therefore, a driving force of the driving motor 150 is transmitted to the subsidiary washing tub 80 through the connection shaft 70, and the laundry in the subsidiary washing tub 80 may be washed together when the laundry in the rotary tub 30 is washed. According to the embodiment of the present invention, when the first pulsator 71 is rotated, the subsidiary washing tub 80 may also be rotated.

The first pulsator 71 may include a plurality of ridge portions 73 which protrude upward to circulate the laundry. According to the drawings, six ridge portions 73 may be provided.

The connection shaft 70 may include a base portion 74 coupled to the first pulsator 71, a neck portion 72 configured to extend from the base portion 74, and a head portion 75 configured to extend from the neck portion 72 and coupled to the subsidiary washing tub 80. The head portion 75 may be provided so that a width of the head portion 75 tapers toward an end thereof in order to guide coupling to the subsidiary washing tub 80. That is, the head portion 75 may be provided in a wedge shape toward the subsidiary washing tub 80. Further, a plurality of grooves 75 a may be provided at the end of the head portion 75 to increase a coupling force with the subsidiary washing tub 80.

The subsidiary washing tub 80 may have a coupling hole 80 b configured to couple the head portion 75. The coupling hole 80 b may be provided at a center portion of the subsidiary washing tub 80. The head portion 75 is inserted into and coupled to the coupling hole 80 b, and at least part of the head portion 75 may be inserted inside the subsidiary washing tub 80 through the coupling hole 80 b. After the head portion 75 is inserted, a sealing member 89 may be coupled to the coupling hole 80 b. Therefore, vibration and noise generated between the head portion 75 and the subsidiary washing tub 80 when the washing machine 1 is operated may be reduced.

FIG. 5 is a view illustrating a disassembled state of the balancer and the subsidiary washing tub in the washing machine in accordance with the embodiment of the present invention.

As illustrated in FIG. 5, in an embodiment, at least one protruding portion 81 may be provided at the subsidiary washing tub 80. The protruding portions 81 may be provided along a circumference of the subsidiary washing tub 80. The protruding portions 81 may be formed to protrude inside the subsidiary washing tub 80. The balancer 90 may have at least one receiving groove 91 to accommodate the protruding portions 81 of the subsidiary washing tub 80. The receiving grooves 91 may be provided to have shapes corresponding to the protruding portions 81.

According to the embodiment of the present invention, a magnet (not shown) may be located inside each of the receiving grooves 91, and a magnetic member (not shown) reacting with the magnet may be located inside each of the protruding portions 81. However, the present invention is not limited thereto. The magnet (not shown) may be located inside each of the protruding portions 81, and the magnetic member (not shown) may be located inside each of the receiving grooves 91. Therefore, the subsidiary washing tub 80 and the balancer 90 may be coupled to each other by a magnetic force. When a user would like to separate the subsidiary washing tub 80 from the balancer 90, the user may separate the subsidiary washing tub 80 by applying a force greater than the magnetic force. Thus, the subsidiary washing tub 80 may be prevented from being separated from the balancer 90 due to the vibration generated when the washing machine 1 is operated.

According to the embodiment of the present invention, since the subsidiary washing tub 80 is provided separately from the rotary tub 30, general laundry and delicate laundry may be separately washed. Therefore, since different types of laundry may be washing through one washing process, the washing process may be effectively performed.

Further, the subsidiary washing tub 80 may be easily separated from the rotary tub 30, and thus when the subsidiary washing tub 80 is not used, the subsidiary washing tub 80 may be separated and used as a laundry storage basket.

Furthermore, since the subsidiary washing tub 80 is rotated together with the first pulsator 71, the washing process may be separately performed according to the type of the laundry, and also a washing force in the subsidiary washing tub 80 may be increased.

FIG. 6 is a view illustrating a coupling state of a rotary tub and a subsidiary washing tub in a washing machine in accordance with another embodiment of the present invention.

FIG. 7 is an exploded view illustrating a disassembled state of the rotary tub and the subsidiary washing tub in the washing machine in accordance with another embodiment of the present invention.

FIG. 8 is a cross-sectional view illustrating a coupling state of a first pulsator and the subsidiary washing tub in the washing machine in accordance with another embodiment of the present invention.

Since elements having the same reference numerals correspond to the same elements, descriptions thereof will be omitted.

According to the embodiment of the present invention illustrated in FIGS. 6 to 8, a first pulsator 71 is located in a rotary tub 30, and a second pulsator 185 is separately coupled in a subsidiary washing tub 80. The first pulsator 71 and the second pulsator 185 are coupled by a connection shaft 70. Therefore, a driving force of a driving motor 150 is transmitted to the second pulsator 185, and thus the second pulsator 185 may be rotated together with the first pulsator 71.

The second pulsator 185 may include a connection shaft coupling portion 182 coupled to the connection shaft 70, and a ridge portion 183 configured to protrude from the second pulsator 185 and enable the washing water to be circulated. The connection shaft coupling portion 182 may be provided at a center portion of the subsidiary washing tub 80.

The second pulsator 185 may be separately coupled to a lower surface of the subsidiary washing tub 80. The subsidiary washing tub 180 may include an insertion portion 186 formed inside the subsidiary washing tub 80 to protrude upward, such that the connection shaft 70 is inserted therein. The connection shaft 70 may be inserted into the insertion portion 186.

According to the embodiment of the present invention, a guide member 187 configured to guide rotation of the connection shaft 70 may be included between the connection shaft 70 and the subsidiary washing tub 180. The guide member 187 may be inserted into the connection shaft coupling portion 182 of the subsidiary washing tub 180 and coupled to the second pulsator 185 through a fastening member 189. Another side of the guide member 187 is coupled to the head portion 75 of the connection shaft 70. Therefore, when the connection shaft 70 is rotated, the guide member 187 is also rotated, and thus the second pulsator 185 of the subsidiary washing tub 180 may be rotated. According to the embodiment of the present invention, the guide member 187 is separately provided, but the present invention is not limited thereto. The guide member 187 and the connection shaft 70 may be integrally provided.

Since the second pulsator 185 and the connection shaft 70 are coupled by the guide member 187, the second pulsator 185 may be rotated together with the rotation of the connection shaft 70, and thus the washing force with respect to the laundry in the subsidiary washing tub 180 may be enhanced. Further, when the subsidiary washing tub 180, which is not used, is separated from the rotary tub 30, the second pulsator 185 coupled to the subsidiary washing tub 180 is also separated, and the user does not need to separately disassemble the second pulsator 185.

According to the embodiments of the present invention, since the laundry can be separately put into the rotary tub and the subsidiary washing tub and then washed at the same time, the washing process can be simultaneously performed according to the type of laundry. Further, since the second pulsator in the subsidiary washing tub is operated according to the operation of the first pulsator in the washing tub, it is possible to increase the washing power of the laundry in the subsidiary washing tub.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

What is claimed is:
 1. A washing machine comprising: a cabinet configured to form an exterior; a tub included in the cabinet and configured to contain washing water; a rotary tub included in the tub and configured to receive laundry; a driving device configured to rotate the rotary tub; a subsidiary washing tub included in the rotary tub and coupled to be removable from the rotary tub; and a connection shaft configured to extend from a lower portion of the rotary tub to couple the subsidiary washing tub to the rotary tub, such that the subsidiary washing tub is rotated together with the rotary tub.
 2. The washing machine according to claim 1, wherein the rotary tub further comprises a first pulsator rotatably installed at the lower portion of the rotary tub to generate a water current and circulate the laundry.
 3. The washing machine according to claim 2, wherein the connection shaft extends from a center portion of the first pulsator.
 4. The washing machine according to claim 1, wherein the subsidiary washing tub further comprises a second pulsator rotatably included at a lower portion of the subsidiary washing tub to generate a water current and circulate the laundry.
 5. The washing machine according to claim 4, wherein the connection shaft is coupled to a lower portion of the second pulsator.
 6. The washing machine according to claim 1, wherein the connection shaft comprises a base portion coupled to the first pulsator, a neck portion configured to extend from the base portion, and a head portion configured to extend from the neck portion and coupled to the subsidiary washing tub.
 7. The washing machine according to claim 6, wherein the head portion is provided so that a width of the head portion tapers toward an end thereof to guide coupling to the subsidiary washing tub.
 8. The washing machine according to claim 1, wherein a coupling hole, to which the connection shaft is coupled, is formed at a lower surface of the subsidiary washing tub.
 9. The washing machine according to claim 8, wherein a sealing member configured to seal the coupling hole is coupled inside the subsidiary washing tub.
 10. The washing machine according to claim 1, wherein a coupling groove, to which the connection shaft is coupled, is formed at a lower surface of the subsidiary washing tub.
 11. The washing machine according to claim 1, further comprising a balancer included on the tub, wherein the subsidiary washing tub is removably coupled to the balancer.
 12. The washing machine according to claim 11, wherein at least one protruding portion is provided along a circumference of the subsidiary washing tub, and the balancer has at least one receiving groove to accommodate the protruding portion.
 13. The washing machine according to claim 12, wherein a magnet is included inside the receiving groove, and a magnetic member reacting with the magnet is included inside the protruding portion, and the subsidiary washing tub and the balancer are coupled to each other by a magnetic force.
 14. A washing machine comprising: a cabinet configured to form an exterior; a tub included in the cabinet and configured to contain washing water; a rotary tub included in the tub, configured to receive laundry, and comprising a first pulsator configured to generate a water current and circulate laundry; a driving device configured to rotate the rotary tub; a subsidiary washing tub included in the rotary tub and coupled to be removable from the rotary tub and comprising a second pulsator configured to generate a water current and circulate laundry; and a connection shaft configured to extend from the first pulsator and connect the first pulsator and the second pulsator so that the first pulsator and the second pulsator are interlocked and rotated together.
 15. The washing machine according to claim 14, wherein the connection shaft comprises a base portion coupled to the first pulsator, a neck portion configured to extend from the base portion, and a head portion configured to extend from the neck portion and coupled to the subsidiary washing tub.
 16. The washing machine according to claim 15, wherein a coupling hole, through which the head portion of the connection shaft passes, is formed at a lower surface of the subsidiary washing tub, and further comprising a sealing member configured to seal the coupling hole.
 17. The washing machine according to claim 15, wherein a coupling groove, to which the connection shaft is coupled, is formed at a lower surface of the subsidiary washing tub.
 18. The washing machine according to claim 14, further comprising a balancer included on the tub, wherein the subsidiary washing tub is removably coupled to the balancer.
 19. The washing machine according to claim 18, wherein at least one protruding portion is provided along a circumference of the subsidiary washing tub, and the balancer has at least one receiving groove to accommodate the protruding portion, and the subsidiary washing tub and the balancer are coupled to each other by coupling the protruding portion and the receiving groove.
 20. The washing machine according to claim 18, wherein a magnet is included inside the receiving groove, and a magnetic member reacting with the magnet is included inside the protruding portion, and the subsidiary washing tub and the balancer are coupled to each other by a magnetic force.
 21. A washing machine comprising: a cabinet configured to form an exterior; a tub included in the cabinet and configured to contain washing water; a rotary tub included in the tub and configured to receive first laundry, the rotary tub comprising a first pulsator rotatably installed at the lower portion of the rotary tub to generate a first water current and circulate the first laundry; a driving device configured to rotate the rotary tub; a subsidiary washing tub included in the rotary tub and coupled to be removable from the rotary tub, the subsidiary washing tub comprising a second pulsator rotatably included at a lower portion of the subsidiary washing tub to generate a second water current and circulate second laundry; and a connection shaft configured to extend from a center portion of the first pulsator to a lower portion of the second pulsator to couple the subsidiary washing tub to the rotary tub, such that the subsidiary washing tub is rotated together with the rotary tub. 